Alien marine fishes in Cyprus: update and new records

The Mediterranean Sea, due to its connection to the Red Sea via the Suez Canal, its heavy maritime traffic, and the effects of climate change is a hotspot of invasion by alien species. A survey carried out around Cyprus during September 2014 documented the occurrence of 25 alien fishes. Seven Lessepsian migrants ( Hippocampus fuscus Rüppell, 1838, Nemipterus randalli Russell, 1986, Ostorhinchus fasciatus (Shaw, 1790), Parupeneus forsskali (Fourmanoir & Guézé, 1976), Pomadasys stridens (Forsskål, 1775), Sphyraena obtusata Cuvier, 1829 and Spratelloides delicatulus (Bennett, 1832) ) were recorded for the first time, increasing to 35 the number of alien fishes recorded around the island. Four of these first records can be considered as 'established', whereas the 2013 first record of Pterois volitans/miles is confirmed by new findings placing the species as newly 'established' in Cyprus. All the recorded alien fishes of Cyprus are Lessepsian migrants, 80% of which can be considered established and four of them are invasive. The rapid increase of alien fish species over time in Cyprus supports the accelerating tropicalisation process observed elsewhere in the Mediterranean over the last decades. Furthermore, the new finding of the tropical Atlantic immigrant Enchelycore anatina (Lowe, 1839) is documented.


Introduction
The Mediterranean Sea is currently a hotspot for marine bio-invasions (Edelist et al. 2013;Katsanevakis et al. 2014a;Nunes et al. 2014). About one thousand alien species have been recorded in the Mediterranean waters with an accelerating rate of discovery (Zenetos et al. 2012). The opening of the Suez Canal in 1869, which created a corridor between two distinct biogeographical provinces, allowed the so-called 'Lessepsian migration' of Indo-Pacific species into the Mediterranean (Por 1978). Other anthropogenic vectors such as shipping or aquaculture contribute significantly to the introduction of alien species in both the Mediterranean (Katsanevakis et al. 2014a) and European seas (Nunes et al. 2014).
As of 2000, 664 marine fish species were listed in the Mediterranean (Quignard and Tomasini 2000). Numerous additional species have been recorded in the last 15 years, bringing the number of Mediterranean marine fishes to about 750 currently, of which nearly one fifth are exotics . Recently Zenetos et al. (2012) revised their list of alien species for the Mediterranean and retained only 126 fishes, removing species of tropical Atlantic origin because their presence could represent a natural range expansion through the Straits of Gibraltar rather than humanmediated introduction. The ongoing warming trend, or tropicalisation (sensu Bianchi and Morri 2003), seems to be allowing successful establishment by some of these migrant species. The list of excluded alien species also included cryptic species that were probably present in the Mediterranean but overlooked in the past, and sharks with vagrant behaviour. Generally, the richness of Mediterranean fishes decreases from the West to the East (Quignard and Tomasini 2000). In contrast, there is a clear east to west gradient for Lessepsian species richness (Coll et al. 2010), with the highest number of records coming from the Israeli-Lebanese coast and eastern Turkey (Golani 1998;Golani 2010;Azzurro et al. 2013). In the eastern (Levantine) basin, exotic fishes represent about 18% of the Mediterranean fish diversity (EastMed 2010;Golani 2010;Golani et al. 2013Golani et al. , 2006Harmelin-Vivien et al. 2005), with most of them being Lessepsian migrants with an Indo-Pacific origin. Ten additional alien fishes were recorded in 2011-2012 and the number of documented occurrences is rapidly increasing (Golani 2010;Zenetos et al. 2012). However, we should also consider that increasing scientific efforts have likely augmented the rate at which exotic species are being discovered. According to Belmaker et al. (2009), Lessepsian fishes would have been introduced at a rate of 0.71 species/yr.
In the last twenty years, an increasing number of Lessepsian species seem to have extended their distributions from the eastern to the western Mediterranean (Galil and Zenetos 2002). Many exotic fishes are now well-established in the Mediterranean Sea, and at least 31 species can be considered as very abundant or dominant in their new environment (Azzurro et al. 2014), 11 of which may be invasive with significant ecological impacts (Katsanevakis et al. 2014b). Furthermore, with the recent completion of the Suez Canal expansion project, increasing rates of introduction are expected for the near future (Galil et al. 2014).
The first alien marine fish to be recorded in Cyprus was Siganus rivulatus Forsskål & Niebuhr, 1775in 1928(Norman 1929. In 1967, the first survey of the alien marine fishes of Cyprus was launched through a joint research program (Biota of the Red Sea and eastern Mediterranean). This project investigated the spread of Lessepsian migrants in the Levantine basin including Egypt, Israel, Cyprus, and Rhodes (Steinitz 1970). Significant findings of exotic fishes in Cyprus were recorded by Demetropoulos and Neocleous (1969). Despite very intensive surveys in Cyprus, conducted by the Joint Research Project of the Hebrew University of Jerusalem and the Smithsonian Institution, no additional Lessepsian species were discovered (Por et al. 1972). Afterwards, the number of recorded alien fishes in Cyprus increased significantly (Katsanevakis et al. 2009) but many of the species that colonized the Eastern Mediterranean are still unrecorded from this island. This relatively low number of alien species was tentatively attributed to the low water temperatures around the island and to the relatively large distance from the continental shores, which is the main route for advancing Lessepsian migrants (Por 1978). The low number of reports of Lessepsian species from Cyprus was also interpreted as being primarily due to a lack of sampling efforts in a wide range of habitats. It was suggested that well-designed surveys to detect and describe the distributions of non-native species in the marine ecosystem of Cyprus would surely uncover many more species from all marine groups (Chartosia and Menicou 2012). First records of non-indigenous marine fishes for Cyprus were much more numerous beginning in the 1990's (Katsanevakis et al. 2009). In Cyprus, Lessepsian fish species represent up to 10% of the biomass of annual artisanal landings over the last few years (Department of Fisheries and Marine Research -DFMR 2006, unpublished data in Michailidis 2010. The field expedition Cyprus-2014 was dedicated to improve the 'Identification and Classification of Chondrichthyans and Actinopterygians from the North-eastern Atlantic and the Mediterranean' (ICCANAM). This handbook project, with available (provisional) online versions, is focused on establishing an inventory of marine fishes in European and adjacent waters, based on collection of specimens, DNA barcoding, and standardized photographs (Iglésias 2014). Specimens newly vouchered during Cyprus-2014 will be presented in the updated versions 11 of the online handbook. The aim of the present study was to provide an updated list of alien marine fishes in Cyprus based on a part of the collections and records collected during the most-recent expedition.

Materials and methods
The field expedition Cyprus-2014 took place from 06 to 27 September 2014 along the coasts of Cyprus Island, in the eastern Mediterranean Sea. Special sampling efforts were dedicated to detecting and collecting exotic species. Specimens were collected by authors close to the shoreline by: snorkelling with hand nets 10 to 40 cm width, commercial spearguns, mini-spearguns using arrows 2 mm in diameter; hand lines; and by angling from the shore. Some collections, photographs, and observations, were also made by SCUBA diving. Fieldwork was carried out in the Republic of Cyprus, mostly in the district of Famagusta and occasionally in the districts of Larnaca and Paphos ( Figure 1, Table 1). Other specimens from coastal fisheries were provided by fishermen from the ports of Agia Triada, Pernera, and Limassol, or collected in the fish markets of Paralimni, Deryneia, Limassol, Nikosia, and Paphos. Fishmongers were asked about the capture locality of specimens to avoid inclusion of fishes caught out of Cyprus waters.  Fresh specimens were photographed in a standard manner, and then tissue samples were taken and recorded under collection numbers (BPS) for future genetic analyses. Voucher specimens were fixed in 4% formalin for a month, then preserved in 80% ethanol, and registered in the ichthyologic collection of the Muséum national d'Histoire naturelle of Paris (MNHN-IC). Diagnostic characters observed on specimens were reported only for species that represent first records for Cyprus. Abbreviations: TL = total length; FL = fork length; SL = standard length (lengths in mm); D = dorsal fin; A = anal fin; P = pectoral fin; V = pelvic fin; LL = number of scales on lateral line; GR = number of gill rakers on first arch; stn = station. Specimens were identified to species level according to the taxonomical characters provided by Golani et al. (2013). The scientific names used follow Golani et al. (2013) with updates according to Eschmeyer and Fricke (2015) and taking into account recent taxonomical revisions for Lessepsian fishes: Azzurro et al. (2015), Doiuchi and Nakabo (2005), Golani et al. (2014), Matsuura et al. (2011), Randall (2013, Randall et al. (2014), and Russell et al. (2015). Establishment success was updated from Katsanevakis et al. (2009). The listed species were classified into the following categories used by Zenetos et al. (2005;: established, casual, questionable, and invasive. Species with at least three records in Cyprus spread over time and space were classified as established . Casual species are those having been recorded no more than twice in both scientific and grey literature and are presumed to be nonestablished in Cyprus. Questionable species are those with insufficient information; this category includes new entries not verified by experts or species with unresolved taxonomic status. Invasive species were defined as established alien species that have overcome biotic and abiotic barriers and are able to reproduce outside of their area of initial introduction with noticeable ecological or economic impact.

Results
We documented the occurrence of 25 Lessepsian fish species plus one Atlantic immigrant, representing 19 families (see also Supplementary Table S1).  13; A: 11 (10); P: 12; V: 8; belly smooth without series of scutes; dorsal fin origin before midpoint; W-shaped scute at the base of the pelvic fin; relatively large scales easily detached with continuous vertical striae across them. The species, which forms shoals consisting of thousands of individuals, was regularly observed during the day near the surface in coastal waters, and commonly at night in compact shoals along the beach in 0-2 m depth. This species is presently a first record for Cyprus, where the observations made during Cyprus-2014 allow it to be considered as established.

MULLIDAE
Parupeneus forsskali (Fourmanoir & Guézé, 1976) A single individual was photographed with a smartphone by a fishmonger (photograph not recovered). According to the fisherman, the specimen, about 15 cm in length, was caught with a net off Agia Triada, stn 14 in the beginning of September 2014, 15 m depth. The retained diagnostic characters were the presence of barbels, a pointed snout, a marked blotch on the upper caudal peduncle, and dark stripes on the lateral sides. The specimen was a first record for Cyprus.

Enchelycore anatina (Lowe, 1839)
A single individual was observed at Cyclope Cave, stn 18, on 16 Sep. 2014, at 5 m depth in a rocky hole. Two others individuals (Figure 4) were observed together at Agio Anargyroi, stn 30, on 25 Sep. 2014, at 7.5 m depth in holes on a vertical wall of coralline seaweeds. A small individual from the Cape Greco area is also visible in a submarine video on the Internet (Scuba Tech Diving Center, Cyprus, 2013). These observations, and additional observations by locals, support the hypothesis idea that E. anatina is now established in Cyprus.

C. Update of alien fishes in Cyprus
Taking into account: 1) the finding of seven alien fishes new to Cyprus; 2) the ten alien fishes reported for Cyprus but not observed during our survey; and 3) the status revision of previously recorded species presented in Table 2, at least 35 alien fish species now inhabit the waters of the island, 28 of which can be considered as established. The rate at which new alien marine fishes are recorded in Cyprus showed a significant increase ( Figure 5). Twelve exotic species were recorded for the first time in Cyprus from 1928 to 1994 (a 66 year time span) whereas 23 aliens species were recorded for first time in Cyprus from 1995 to 2014 (a 20 year time span).

Discussion
The Cyprus survey identified seven new Lessepsian fishes (Hippocampus fuscus, Nemipterus randalli, Ostorhinchus fasciatus, Parupeneus forsskali, Pomadasys stridens, Sphyraena obtusata and Spratelloides delicatulus), increasing to 35 the number of alien fish species dwelling in the waters of the island. The study also serves as an update for the establishment success of alien fishes already recorded in the island. Finally, these new data improve knowledge on the establishment of a tropical Atlantic species, the recently recorded Enchelycore anatina.

Excluded species or records
In the updated list of alien fishes for Cyprus (Katsanevakis et al. 2009), Himantura uarnak (Forsskål, 1775) is listed as 'questionable', based on Last and Stevens (1994). In a general comment on world distribution, the authors mention the species in the eastern Mediterranean. The world map presenting the distribution for the species includes Cyprus but it is imprecise at the regional scale. Some records of that species exist in the Table 2. Updated checklist of the alien and tropical Atlantic marine fishes for Cyprus. Species are presented in reverse chronological order of records for Cyprus. In the case where the date of collection of a first record remains unknown, the date of publication was used instead accompanied with the symbol '<'. (* = observed during the expedition Cyprus-2014; Medit. = Mediterranean, E = East, W = West).  Katsanevakis et al. 2009 eastern Mediterranean  but there is to confirm that Last and Stevens (1994) actually observed this species in Cyprus. As a consequence the reference of Last and Stevens (1994) is not retained as first record of H. uarnak for Cyprus. Debelius (1997, p. 20) presents an underwater photograph of a specimen of H. uarnak with the footnote "Cyprus". According to Debelius (pers. com.) the locality "Cyprus" as a footnote was incorrect and the photograph was taken off northern Beirut in Lebanon in early 1977.
Consequently there is currently no valid record of H. uarnak for Cyprus. In a similar manner, in the updated list of alien fishes for Cyprus (Katsanevakis et al. 2009), Herklotsichthys punctatus and Dussumieria elopsoides are recorded as 'casual' and 'established' respectively based on Whitehead (1985). In a general comment on world distribution the author mentions the species in the eastern Mediterranean but does not mention actual records from Cyprus. These species appear to be established all around Cyprus but the present reference (Whitehead 1985) could not be considered as a first record. D. elopsoides is recorded in Cyprus by Gitarakos et al. (2007) (Golani and Fine 2002) and later recorded in Turkey (Gökoğlu et al. 2004). Ostorhinchus fasciatus was first recorded in the Mediterranean in 2008 in Israel (Goren et al. 2009) then extended its distribution to Turkey (Gökoğlu et al. 2012). Parupeneus forsskali was recorded first in the Mediterranean in 2012 in Lebanon and Israel where it is known by a single collected specimen and some unsubstantiated records (Bariche et al. 2013b). Pomadasys stridens was first recorded in the Mediterranean in the Gulf of Genoa in Italy (Torchio 1969) but it appears to be established only in the eastern Mediterranean.
Among the 35 alien marine fishes of Cyprus, 34 are Lessepsian migrants. Only one unexpected species (Acanthurus coeruleus Bloch & Schneider, 1810) has a western tropical Atlantic origin. Its introduction pathway remains unknown (Langeneck et al. 2012). All species recorded before 2009 have currently an established or invasive status suggesting that when an alien species migrates to Cyprus it successfully naturalizes. Consequently it could be predicted that the same establishment success will occur for other species with a casual status recorded since 2009.

Immigration rate
In marine waters of Cyprus, the number of new exotic fish species recorded per year, was 0.41 from 1928 (year of the first record of an alien fish in Cyprus) to 2014. The rate of first recording was 0.18 per year pre-1995, and then grew to 1.15 per year post-1995 -an apparent 6.3 fold increase between the two periods ( Figure 5). This acceleration process of introduction is well documented in the Mediterranean Sea (Galil et al. 2002;Zenetos et al. 2012) and it appears after a sharp increase in water temperatures detected in the 1990s in the eastern Mediterranean (Raitsos et al. 2010;Macias et al. 2013). Nevertheless this apparent increasing introduction rate of exotic fishes in Cyprus can be also an artefact reflecting the increased sampling effort (Belmaker et al. 2009). The two hypotheses are not mutually exclusive.

Invasive species
The four invasive fishes present in Cyprus (Fistularia commersonii, Siganus luridus, Siganus rivulatus, and Lagocephalus sceleratus) are considered to have a high-impact in the Mediterranean Sea (Katsanevakis et al. 2014b). The first three are landed by coastal fisheries, where they are of some commercial interest (Chartosia and Menicou 2012). L. sceleratus, having arrived only ten years before in Cyprus, has a significant negative impact on the artisanal fishery since it often damages both the fishing gear and the catch of the fishermen; moreover, it represents a potential risk to humans because it contains tetrodotoxins, which are toxic to humans (Michailidis 2010;Nader et al. 2012;Rousou et al. 2014). The average time that was needed by alien fishes to reach the waters of Cyprus after entering the Mediterranean was 25.2 years (range 0 to 76 years). For the four invasive species present in Cyprus, the average time was only 6.5 years (range 0 to 24 years) consistent with invasive species having a high dispersal rate in their new environment, at least for the particular case of Cyprus. The venomous Pterois volitans/miles species complex has recently been recorded in the Mediterranean, and Cyprus need to be particularly monitored in light of the rapid invasion of this species complex in western Atlantic tropical waters (Albins and Hixon 2013). Surprisingly, oceanographic models indicate that invasion of the Mediterranean by P. volitans/miles was unlikely to occur (Johnston and Purkis 2014). However, the morphological peculiarities (e.g. the elongated fin rays) of this species complex are so distinctive from other Mediterranean fishes that it unlikely to be misidentified, and its venomous nature could represent an adaptative advantage in this new environment (Azzurro et al. 2014).

B. First and additional records of tropical Atlantic species
The tropical Atlantic Enchelycore anatina has been excluded from the previous inventories of aliens for the Mediterranean because its presence can be explained by a natural expansion of their tropical Atlantic range through the Straits of Gibraltar rather than as human mediated introduction (Zenetos et al. 2012). E. anatina was first recorded from Cyprus in 2008 and considered as 'casual' (Katsanevakis et al. 2009). According to the present observations the species can now be considered established in Cyprus.